Generally, the abilities that channellers develop can be pretty much anything you can possibly imagine. Typically speaking however, the powers commonly manifest as one of 4 different categories: Augmenters, Wavecasters, Architects and Alternatives
Augmenters are those who use their energy to enhance or alter their own bodies and physical abilities. This can manifest in a number of ways, such as increasing their physical strength, giving themselves faster reflexes and reaction times, being able to see through walls, and much more. They are the most straightforward of channellers, and so there isn't too much to say about them. Due to their focus on their bodies and physical abilities, Augmenters are usually stereotyped as the "strong but dumb" type of people
Wavecasters are those who use their energy to control and manifest types of energy (excluding one's inner energy, of course). By far the most common type of Wavecaster is one who creates simplistic things, such as the 4 elements. However, it's also possible to make and control things like electricity, smoke and lasers, and even stranger and abstract things such as shadows, light and sound waves. Architects are by far the most common type of channellers, and therefore don't really have a stereotype about them due so many different people being that type
Architects, much like Wavecasters, use their energy to create and manifest objects, but these channellers are based more around solid objects instead of energy, such as swords, guns, bombs, armor, and much more. They are limited by the type, number and complexity of the objects they can create, so they can't create an infinite number of an object, they cant create any type of object they want at any time (so a blade channeller can only create things like swords and knives), and they have to understand how the object is constructed and functions in order to create it, so complicated things like machines are limited to people who can fully understand them. Architects can also create a certain type of animal, though they can only create empty bodies that they control, they can't create actual life. These channellers can also control already existing things as well (so a sword channeller can also control swords that he didn't create). This also works for animals as well, kind of like mind control for the animal. Architects tend to be seen as smart, logical and strategically minded, but also heavily reliant on tactics, having other things protecting and fighting for them and not being able to actually fight
Alternatives are those whose energy manifests in some other way. The rarest of the 4 categories, these people are outliers that defy the other 3 categories either by having a power that could fit into more than one category, or don't really fit ANY of the categories. Powers such as the ability to alter and negate someone else's energy, clone themselves, change the shape of their body, etc. Alternatives are usually stereotyped as weirdos, freaks and unpredictable